The invention relates to a high-power illumination device integrated with a camera for measuring the direction, distance and/or attitude of two objects relative to each other. One of the objects carries the device, and the camera images the other object on a detector via an input-optical system. The device has a plurality of elementary sources each associated with an optical system for adjusting the field of view of each source to that of the input-optical system of the camera.
A device of this type is used, for example, in encounters between two objects in space, one of which is referred to as the "hunter" which is to make contact with the other object referred to as the "target".
It is necessary that the coupling between the two objects is established with the least possible mechanical shock at the instant of contact so that the orbital conditions of the target are not modified too much.
For this purpose the hunter must take the theoretical orbit of the target into account at a sufficiently early moment in order to contact it at the right speed and particularly at the right attitude.
This requires equipment installed in the hunter and measuring the distance between the hunter and the target (for the final approach they may take up positions at, for example 200 m) the direction of the target with respect to the reference mark of the hunter and the attitude of the target with respect to this mark.
This equipment comprises a camera provided with a radiation emitter emitting a certain cone of radiation along the same axis and in the same field as that of the camera, which cone is projected onto the target on which retroreflectors have been disposed, i.e. small mirrors having three faces (or corner tubes) which return the reflected beam along itself, independent of their position in space.
A laser diodes commonly used as light emitter necessitate the use of an optical system for adapting the angle of the emitted cone to the field of view of the camera.
For spatial encounters between two objects it is necessary to use an emitter which is sufficiently powerful so that the luminous flux coming from the retroreflectors and impinging upon the camera is stronger than that emitted by the sun.
Consequently, several elementary sources each comprising a laser diode and a optical system must be used for enhancing the power of the emitter to a considerable extent. It is difficult to arrange these sources in a very small space and such that they emit in one and the same cone.